Subsoil caves characterization by means of the interpretation of electrical resistivity tomography: Application to Clunia and Atapuerca archaeological sites

Abstract

The aim of this research is to develop a suitable methodology for the interpretation of Electrical Resistivity Tomography (ERT) images from the subsoil (obtained with direct-current), specifically applied to the detection of caves, holes and the structural characterization of a karstified limestone formations related to archaeological sites. The location and characterization of holes and caves by means of the geophysical technique is nowadays being resolved in various several ways, because there is not a clear and safe method for the resistivity profile interpretation. This work complies a novel series of tests performed on well-known objectives that analyses the effects of the main factors that condition resistivity images. This work has been two different practical parts: (1) Laboratory test: Electrical response tests performed on well-known objectives. (2) Field work: ERT applied to prospect the endokrast morphologies and the sedimentary infills of two archaeological sites in Burgos (Spain), the roman city called Colonia Clunia Sulpicia and the Pleistocene archaeo-palaeoanthropological sites of Atapuerca. The operations needed to obtain subsoil images by using Electrical Resistivity Tomography are relatively simple; however their after interpretation is very complex. By performing controlled tests it has be identified the areas that offer a specific electrical response according to several different sub-soil models and to the multielectrodical device used.